Fortis b 42 marinemaster chronograph 6381041 m fortis b 42 marinemaster chronograph watches are the ultimate instrument for professional divers each timepiece is equipped with swiss made valjoux 7750 automatic calibre that performs 28 800 vibrations per hour and has 25 bearing jewels other movement characteristics include incabloc shock absorber and fine timing device hands numerals and indices are covered with luminous paint to enhance night time readability a day and date display is po